The present invention relates to a printing apparatus including a printing assembly and a paper feeding device for feeding individual sheets of paper one after another from a paper storage stacker to the printing assembly along a paper inlet path. More particularly, the invention is concerned with such paper feeding device which provides another paper inlet path along which sheets of paper of another kind are loaded to the printing assembly.
In the art of a paper feeding apparatus having a paper stacker or tray for storing a stack of paper sheets of one kind, it has been required to remove the paper stacker from a printer when it is desired to print on a sheet of paper of another kind which is different in size or format from said one kind. This removal of the stacker which is required to permit loading of said another kind of paper sheet without interference with the paper stacker, is combersome and time-consuming. There is also available in the art another type of paper feeding apparatus which has two paper stackers for feeding respective two kinds of paper different in size or format. In this type of feeding apparatus, one stacker is used for storing frequently used kind of sheets and the other for storing another kind of sheets which are less frequently used and on which an interruption printing is effected while successive printings on the frequently used sheets are stopped temporarily. This two-stacker feeding apparatus is inherently complicated in construction and has a drawback that two or more sheets superposed for carbon copies are not smoothly and accurately fed because the feeding device acts on only the top sheet of a paper stack in the storage stacker.
On the other hand, a printing apparatus having a paper feeding device is usually provided with an automatic paper insertion and guide assembly to insert a sheet of paper from a stacker along the circumference of a platen and advance the inserted paper sheet up to its printing start position. However, since the amount of paper feed and advancement by the feeding device and the insertion and guide assembly is fixed for the sheets of paper stored in the paper stacker, it has been required to adjust the amount of paper advancement when a sheet of paper of another kind is loaded for printing during interruption of a printing operation on the sheets of paper fed from the paper stacker.